[gcc(refs/users/aoliva/heads/testme)] libstdc++: async: tolerate slightly shorter sleep

[Alexandre Oliva <aoliva@gcc.gnu.org>]

https://gcc.gnu.org/g:576499b2ab9d87a331b5408c81012cf1d424f9d9

commit 576499b2ab9d87a331b5408c81012cf1d424f9d9
Author: Alexandre Oliva <oliva@adacore.com>
Date:   Mon Jun 20 20:44:27 2022 -0300

    libstdc++: async: tolerate slightly shorter sleep
    
    Even without frequent signals interrupting nanosleep, sleep_for on
    rtems on qemu wakes up too early by a predictable margin of less than
    0,3%, which some async tests complain about the too-short wait times.
    Allow the tests to tolerate a little sleep deprivation.
    
    
    for  libstdc++-v3/ChangeLog
    
            * testsuite/30_threads/async/async.cc: Tolerate early wakeup.
    
    TN: V608-048

Diff:
---
 libstdc++-v3/testsuite/30_threads/async/async.cc | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/libstdc++-v3/testsuite/30_threads/async/async.cc b/libstdc++-v3/testsuite/30_threads/async/async.cc
index 38943ff1a9a..b151677af6a 100644
--- a/libstdc++-v3/testsuite/30_threads/async/async.cc
+++ b/libstdc++-v3/testsuite/30_threads/async/async.cc
@@ -104,7 +104,8 @@ void test03()
   VERIFY( status == std::future_status::ready );
 
   auto const elapsed = CLOCK::now() - start;
-  VERIFY( elapsed >= std::chrono::seconds(2) );
+  auto const tolerance = std::chrono::milliseconds(6);
+  VERIFY( elapsed + tolerance >= std::chrono::seconds(2) );
   VERIFY( elapsed < std::chrono::seconds(5) );
 }
 
@@ -169,7 +170,8 @@ void test_pr91486_wait_for()
   auto status = f1.wait_for(wait_time);
   auto const elapsed_steady = chrono::steady_clock::now() - start_steady;
 
-  VERIFY( elapsed_steady >= std::chrono::seconds(1) );
+  auto const tolerance = std::chrono::milliseconds(3);
+  VERIFY( elapsed_steady + tolerance >= std::chrono::seconds(1) );
 }
 
 // This is a clock with a very recent epoch which ensures that the difference
@@ -222,7 +224,8 @@ void test_pr91486_wait_until()
   auto const elapsed_steady = chrono::steady_clock::now() - start_steady;
 
   // This checks that we didn't come back too soon
-  VERIFY( elapsed_steady >= std::chrono::seconds(1) );
+  auto const tolerance = std::chrono::milliseconds(3);
+  VERIFY( elapsed_steady + tolerance >= std::chrono::seconds(1) );
 
   // This checks that wait_until didn't busy wait checking the clock more times
   // than necessary.